1. Field of the Invention
The present invention relates to a display panel, an electro-optical device, and a method for fabricating the same and, more particularly, to improve the tilt conditions of the liquid crystal molecules in a display panel which eliminates the dark-state light leakage.
2. Descriptions of the Related Art
With the continuous advancement of technologies, a wide variety of electronic products have become indispensable. Particularly, the display devices play an important role in multimedia electronic products. Among various displays, the thin film transistor liquid crystal displays (TFT-LCDs) have some advantages, such as low power consumption, no radiation, small size, a flat panel profile, high resolution, and stable display quality. As a result, TFT-LCDs are being widely used in place of conventional cathode ray tube (CRT) displays in many electronic products, such as mobile phones, display screens, digital TV sets, and notebook computers.
With the rapid development of technologies related to TFT-LCDs, improvements to the image displaying quality thereof have become targeted in this field. For example, the technology of the multi-domain vertical alignment (MVA) developed by FUJITSU Corporation has extended the viewing angle in the vertical direction to about 120°, which enhanced the viewing angle of LCDs.
An LCD which displays an image in a mode where light from a backlight module is transmitted through a color filter is known as a “transmissive type LCD”, in which a substantial portion of the power consumption is attributed to the backlight module. The brighter the LCD display, the more power the backlight module consumes. Moreover, under bright environments, the displayed images are prone to interference from ambient light, which may render the images unclear. In contrast, a reflective type LCD displays an image by reflecting ambient light, which, may be consumer less power, but exhibits a poor contrast ratio, a degraded color saturation, and cannot display images clearly in dark conditions. To overcome these problems, the transflective type LCD comes up as a compromise between the transmissive type LCD and the reflective type LCD. Since it uses both backlight and natural light or artificial light, the transflective type LCD is used in many circumstances, and consumes less power than the transmissive type LCD.
Currently, the transflective type LCD with a MVA design has a protrusion disposed in the transmissive area and the reflective area on the side with the color filter. Such a protrusion may change the distribution of the electric field, making liquid crystal molecules tilt towards the protrusion at a pre-tilt angle, i.e., perpendicular to the surface of the protrusion in different directions. With such a protrusion, the multi-domains of liquid crystal molecules can be achieved, which resulting in a wide viewing angle range and further improving the gray-scale inversion problem as found in single-domain cases.
In the prior art designs of LCD pixels, each sub-pixel has only one common line and only one scan line (i.e. a gate line) disposed therein. In this case, a potential on the scan line will go higher than that on the common line when the TFT is switched off in micro-second (μsec). For example, in a low temperature polysilicon (LTPS) technology, a scan line is exposed to an 11 V potential when TFT is switched off in micro-second (μsec), while the common line stays at 0 V A higher electric potential difference between the common line and the scan line tends to cause uneven an electric field distribution on both sides, which may result in different tilt degrees of the liquid crystals and an irregular arrangement of liquid crystals near the scan line, thus leading to a dark-state leakage and degraded contrast ratio.
In summary, the existing TFT-LCDs with the MVA design exhibit an irregular arrangement of liquid crystal molecules when powered on, which may result in a low efficiency of liquid crystal molecules and affect the brightness distribution. Furthermore, there is a dark-state light leakage and degraded contrast ratio, thereby adversely affecting the image displaying quality. Therefore, it is highly desirable in the art to find a way to improve the liquid crystal arrangement, thereby to eliminate light leakage.